1. Field of the Invention
The present invention relates to a focus state indicator for a camera.
2. Description of the Prior Art
In a conventional indicator for letting the photographer to know a focus state by means of a sound generating unit such as a buzzer, a distance between a camera and a subject to be photographed is measured by a means of optical or ultrasonic transmission and reception. The measured distance is compared with a position of a photographic lens to determine the focus state. When the photographic lens is in the state in which the subject is focused on the focusing surface, a sound is generated to let the photographer to know the focus state. Furthermore, a means is also utilized in which sounds are generated at different periods or intervals respectively in the focused and out of focused states.
Although the conventional focus state indicator with a sound generating unit can distinguish the focused state from the out of focused state, it cannot designate the subsequently required focusing operations such as the rotational direction of the focusing ring or its proper angular displacement, resulting in inconvenience.
A light-emitting element is known as a means for letting the photographer to know the focus state. Even in such an element, the rotational direction of the focusing ring and its angular displacement cannot be signalled.